This invention relates to a conveyor stub idler roll apparatus and particularly to means for adjustably mounting a stub idler roll to a conveyor for edge support of the return run of an endless flexible side wall conveyor belt.
This invention is an improvement to my previous inventions disclosed in U.S. Pat. Nos. 4,844,241 and 5,027,940, which are incorporated herein by reference.
The movement of industrial products in the form of particulate and fibrous materials has for years been conveniently done using flat belt conveyors having corrugated sidewalls and cleats secured to the top of the belt, which form pockets in the conveyor belt. Such conveyors are capable of running horizontally, turning up at steep angles (to 90° or vertical) then turning once more to the horizontal position to discharge. Belt speeds range from 150 feet per minute to 500 feet per minute and faster, which subjects the idler bearings and drive system to relatively severe operating conditions.
Stub idlers are cantilevered rollers which run freely on the outboard extension of the base belt on the conveyor, thereby allowing side walls of the belt to hang free between stub idlers on opposite edges of the belt on the return side. Initially, these units were manufactured in the same way as conventional return idlers, having support bearings mounted directly in the roller itself U.S. Pat. Nos. 4,844,241 and 5,027,940 relate to a stub idler unit which supports a larger diameter solid shaft in order to handle high cantilevered loads. The stub idler unit includes bearing support means which are mounted in a support bracket for coupling the idler unit to a stationary support on the conveyor. The stub idler unit includes a shaft which is journaled on the outside of the roller. The shaft accommodates standard, generally accepted roller bearing sizes used throughout the idler industry. The bearing support includes means for lubrication of bearings while the conveyor is in operation.
Experience has shown that rather than mounting the stub idlers in a horizontal position, there is better supporting contact between the belt and the idler if it is declined at an angle. Angling the stub idler roll at a declined angle from center accommodates the natural flexibility of a rubber belt, even though the belt is typically constructed with a cross rigid truss ply. The declining attitude also helps the belt to track better and center itself between the horizontal members of the conveyor frame. In the United States, the conveyor industry has adopted angles of 3° and 5° for typical stub idler mounting. However, there are also applications in which the idlers are mounted with their rotational axes horizontal.
Experience has also shown that during conveyor operation, it is often necessary to change stub idler roll units, as required for maintenance, repair, or replacement of the idler roll. In addition, to reconfigure a conveyor system, it is often necessary to replace existing idler roll units with roll units having rolls of differing diameters. Finally, in order to accommodate stub idler applications with the idler axes at 0°, 3° and 5°, suppliers are required to stock many different mounting shapes and sizes.
It is therefore desirable to provide a mounting mechanism for stub idler rolls that facilitates adjustment in pitch of the stub idler roll to accurately position the roll along the edge of the belt so there is a clearance from the sidewall of ¾ in. or 15% of the recess, whichever is larger, to prevent sidewall wear. It is also desirable to provide mounting means for a stub idler unit that facilitates replacement of idler rolls. It is desirable to provide such a mounting means which is simple and easy to use and consists of a minimal number of parts to minimize the chance for mechanical breakdown. Finally, it would be most desirable to provide a universally adjustable mounting bracket that would accommodate all standard mounting angles, as well as vertical adjustment of the stub idler on the conveyor support structure.